Installation, operation and maintenance instructions
High voltage flameproof motors for explosive atmosphere
AMD Rg 355-400-450-500
Horizontal motors with rolling bearings – Assembly and
disassembly instruction
Issued by: MOLM
Sheet No.
3AAM101047 E
Rev. B 01.2023
Page 3 of 4
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Important!
The explosion-proof motors are only to be serviced by
trained, certified personnel, following the opportune
instructions and preferably under the supervision of
an
Service organisation. The maintenance
operations are to conform to the requirements
specified in the IEC Standards 60079-17 and 60079-
19.
Dismantling the machine
The following sequence of operations applies to the
normal maintenance jobs that could be required
during the course of general overhauls.
Disconnect all the electric cables and connections
from the power supply line, auxiliaries, control
instruments and ground connections. Remove or
detach the greaser tubes.
From the side opposite the coupling, remove the
fan cover and the external fan, as well as any
temperature sensors and external auxiliary
devices.
remove the devices fastening the motor to the
base-plate and any location pins, and uncouple
the end of the shaft from the driven machine.
Dismantle the coupling joint from the end of the
shaft (see 3AAM101031). If the machine has a
joint on the two ends of the shaft, remove both
joints.
With the pliers remove the split rings that fasten
the bearing seals (10).
Remove the labyrinth rotating seals integral with
the grease valve (14) taking them out with
appropriate threaded tie-rods; these components
are mounted on the shaft with a slight interference,
therefore, to remove, they should be warmed to
approx. 80°C using a flame or hot air (some
machines have the labyrinth seal separated from
the grease regulation rotating valve).
Removal of seals with puller
Remove the screws (4) and the fixed covering of the
bearing (5) The figure shows the seals removal
operation using a puller.
Note: Some design solutions require that the
external seal and the grease valve are incorporated
in a single component.
Using a crane or a jack, raise one end of the
shaft slightly (preferably starting from the
coupling side) so as to remove the weight of the
rotor from the bearing rest the lifted end on a
solid support.
Remove the screws (16) that join the shield (15)
to the casing. Attach the top of the shield to a
lifting device, using an appropriate threaded
ring.
Remove the shield from the casing (on side
corresponding to the end of the unloaded shaft)
using two appropriate bolts inserted in the
threaded holes on the shields. The shield (15)
can thus be extracted taking the necessary
precautions, then rested on the shaft. At this
point the bearing (1) remains fitted on the shaft,
and also the flame-arrester (5) remains in its
place.
Repeat the same operations to dismantle the
opposite shield.
Protect the exposed areas of the bearings
wrapping them in oiled paper or using clean
rags.
Insert a layer of protection (presspan or
cardboard) in the stator pack hole, between the
rotor and the stator magnetic pack.
With a crane or jacks, slightly raise the complete
rotor so as to be able to remove the shaft-end
resting supports, and rest the complete rotor on
the stator, by means of the inserted protections.
Remove the shields from the rotor.
Wind a cardboard or other suitable material tube
around one of the shaft ends. Insert a steel tube
of appropriate diameter onto this protection so
as to obtain an extension of the shaft, and with
suitable
lifting and transfer
equipment
(preferably a crane), extract the rotor from the
stator hole. To extract the rotor, free space is
required of a length equal to that of the machine.
Important! During the above operations, be
very careful to avoid any impacts that could
damage the internal surface of the stator
magnetic pack, the electrical connections
and the flame extinguisher couplings.
-
Special care is to be taken when removing the
bearings from the shaft. Use the specific tools
to remove the bearings, that apply pressure
only on the inner ring of the bearing. Bear in
mind that the clamping between the shaft and
the inner ring has an interference to prevent the
bearing rotating on the shaft when working. The
bearing isolation (if foreseen) is obtained by a
layer of special material inserted in the shield
